System of power generation and storage.



Y PATENTED JULY 17, 1906-.

W. J. CLARK. SYSTEM OF POWER GENERATION AND STORAGE.

APPLICATION FILED JANJT. 1899.

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WILLIAM J. CLARK, OF NEW YORK, N. Y.

SYSTEM OF POWER GENERATION AND STORAGE.

Specification of Letters Patent.

Patented July 17, 1906.

Application filed January 17,1899. Serial No. 702.408.

To all whom, it may concern:

Be it known that 1, WILLIAM J. CLARK, a citizen of the United States,residing at New York, in the county and State of New York, have inventedcertain new and useful Improvements in Systems of Power Generation andStorage, of which the following is a specification.

This invention relates to improvements in power generation and storage;and its object is to provide a steam-power plant with an auxiliary meansof storage of energy in a fluid-pressure reservoir, such fluid beingstored under pressure by the superfluous power of the steam-engines ofthe plant when the load is light and the fluid so stored being deliveredto the steam-engines to increase the power of same when the load isexcessive. Thus in applying my invention to the usual electric-lightingplant, where a plurality of steam-engines or steam-power units operatedynamos connected in parallel to a working circuit, I provide one ormore of the engines with a pump which is brought into operation at timeswhen the load is less than corresponds to the number of steam-powerunits in operation to compress air into a reservoir, and I also providemeans whereby this compressed air may be supplied to the steam-enginesas an auxiliary motive fluid under conditions of excessive loadthat isto say, at the so-called peak of the load.

In the accompanying drawings, which form a part of this specification,Figure 1 is a diagrammatic representation of a steampower plant with myauxiliary storage means applied thereto. Fig. 2 illustrates a loaddiagram with the various steps of storage and delivery of compressed airindicated thereon.

The steam-power plant illustrated in Fig. 1 comprises the twosteam-engines A and A and the two dynamos B and B, driven thereby,feeding in parallel into the working circuit 1 1, which includes theload L. Each of said steam-engines will usually be of the compound type,comprising a high-pressure cylinder 2 and a low-pressure cylinder 3, areceiver O or O being interposed, as usual, in the connection betweensuch cylinders. The respective l1igh-pressure cylinders are connected,through the valves 4 4., with the steammain 6, and a connection 7 leadsfrom the low-pressure cylinders to the exhaust-stack 8. All the aboveelements, with the appropriate valves, &c., are of the usualconstruction and arrangement and need not be further described. Theremay be any number of steam-power elements.

Mechanically connected to each of the steam-engines A or A is anair-pump P or P, the piston 9 of which may be carried by an extension 10of the piston-rod 10 of the steam-engine. These pumps are provided withthe usual valves and are connected, through pipe 11, to a fluid-pressurereservoir D, valves 12 12 being interposed in the connections 13 13between the pumps P P and the pipe 11. From this reservoir D a pipe 14runs to both of the steam-engines A A,valves 15 15 being arranged in therespective connections 16 16 between the air-pipe 14 and the engines AA. The connections 16 16 preferably lead to the receivers C O,intermediate between the high and low pressure cylinders of thesteam-engines. It is desirable that the valves 12 12, controlling theoutlet of the air-pumps P P, should be three-way valves, which whenturned to shut off the connection to the reservoir will open outlets(indicated at 0 0) to the outer air, so that the pumps will then runfreely. The intakes of the pumps are indicated at n and a, respectively.

I will now explain the operation of my in* vention with. the aid of thediagram in Fig. 2, wherein the curved line 00 0: represents theload-curve or curve of power delivered by the engines to the workingcircuit, it being understood that the operator in charge of the plantwatches the load on the external circuit, as shown by suitableindicating means, and manipulates the valves 17 1 4 15 15 to vary theoperation, as hereinafter set forth.

Assuming the load to be at a minimum, so as to be considerably less thanthe capacity of either of thesteam-power units A A, then only one ofthese units, as A, is connected to the steam-main, and the pump P,connected to such unit, is brought into operation by establishingconnection from same through valve 12 with reservoir D, so as to run airunder pressure into this reservoir. This condition corresponds tosection a of the loaddia gram in Fig. 2. When the load increases to apoint commensurate with the capacity of engine A, (section b in Fig. 2,)the pump P is disconnected. In Fig. 2 the load is shown increasingcontinually to a maximum limit, and the capacity of the power plant istherefore increased correspondingly by the following steps: When theload exceeds the capacity of a single engine A, the steam is turned IIOon to the other engine; but as this gives a power rar in excess oi theincrease o'l: load indicated in section 0 of Fig. 2'both the pumps P Pare brought into operation to compress air in the reservoir D. As theload increases the pump 1 may be disconnected, (section d,) and then onthe further increase oi load both pumps may be disconnected, (section0.) l he steam-engines are now working directly on the load, whichabsorbs their full capacity. On further increase of the load, which isassumed to occur at a maximum of short duration, termed peak of theload, the engines would be temporarily overloaded to a dangerous oreven. prohibitive extent unless their normal capacity is made largely inexcess of the usual working requirements. To avoid this, I arrange todeliver the stored air in reservoir D to such a point in one or both ofthe engines A A that the power of such. engines is temporarilyincreased. The pressure in air-reservoir D may be main tained at a pointabove the average Working pressure of the low-pressure cylinder, so thatwhen the compressed air from said reservoir is admitted into one or bothof the receivers C C it will increase the pressure in the lowpressurecylinder and correspondingly aid the engine in overcoming the excessivetemporary load. As is well known, the pressure in receivers C Ofluctuates, being equal to the back pressure of the high-pressurecylinder previous to the opening of the entrance-port into thelow-pressure cylinder, and upon the opening of the port of thelowpressure cylinder and after the piston in said l0w-pressure cylinderhas commenced its stroke the pressure in the receiver falls oil. At thispoint the compressed air admitted to the reservoir becomes eflective inaiding the engine. Thus during the time corresponding to section of Fig.2 the air-pressure is admitted to receiver C of engine A, and at themaximum or peak of the load g the air-pressure is admitted to thereceivers C C of both engines A A. The compressed air mixes with thesteam in the receivers, and the mixture passes to the low-pressurecylinder of the engine or engines. The pressure of the compressed air inreservoir 1) is considerably less than. that in the boiler and, in fact,should be about equal to the normal back pressure in the high-pressurecylinder, so that there is no tendency of the air to pass through. orinto the high-pressure cylinder. The air-pump is put out of actionwhenever the pressure rises above this point. This invention. thereforeenables a steam-power plant of a given capacity to run temporarily on aload lar exceeding such capacity on power stored up during intervals01'' light load. It also enables the throwing in or out of a steam-powerunit without a sudden change in the ratio of power to load, as thedifference is largely absorbed in the pump.

I have also shown in Fig. 1 an additional means of storage andmodification of load and power relation consisting of an air-engine E,capable of acting as a pump or as a motor connected through pipe 18,containing valve 17, to the pipe 11 and the reservoir D. Said pump orengine E is operatively connected to a dynamo-electric machine F, whichis connected to the line 1 1 in parallel with dyna mos B B. At timeswhen the load is in excess of the capacity of the steam units then. inoperation, but not sul'liciently so to justify the coupling up ofanother steam unit, the requisite modification of relation of power toload can be obtained by connecting in this auxiliary apparatus, which.in this case acts as an air-motor, operating the dynamo F to supplyelectrical energy to the line, and under the reverse conditions the sameapparatus may be used to store compressed air in the reservoir D by theaction of dynamo F acting as a motor to drive pump E. In order to eflectthis change of function of this apparatus, it is only necessary to varythe relative force of the engine E and the dynamo-electric machine F.Thus I have shown a regulating resistance II for modifying thefieldexciting current of the dynamo, and thus causing the electromotiveforce generated in such dynamo to exceed or fall below the lineelectromotive force, according to whether it is desired to operate as agenerator or a motor.

Having thus described my invention, what I claim as new therein, anddesire to secure by Letters Patent, is-

1. In a system of power generation and storage, the combination of aprime mover, the fluid-pressure pump connected therewith, means to storethe lluid-pressure generated by the pump, connections from the storagemeans to the prime mover whereby the fluid-pressure generated maybeutilized to assist the prime mover, and an auxiliary fluidpressuredevice operating either as a motor or as a pump to assist the primemover or absorb a portion of the energy generated thereby.

2. In. a system of power generation and storage, the combii'iation of aprime mover having a plurality of working cylinders operating atdifferent pressures, a fluid-pressure pump connected to said primemover, a reservoir connected to said pump for storing the fluid-pressuregenerated thereby, and the connection of said reservoir to the cylinderof the prime mover working at the low pressure.

3. In a system of power generation and storage, the combination of aplurality of steam-power units, each having a plurality of workingcylinders working at difl'erent pressures, an air-pump having mechanical0011-,

nection with one of said units, a compressed air reservoir connected tosaid pump and also connected to a steam-power unit at a point where theworking pressure is below the highest working pressure of thesteam-power unit, and valves in the connections from said reservoir tothe pump and the engine, substantially as and for the purpose set forth.

4. In a power plant, the combination of a steam-engine having aplurality of working cylinders working at different pressures, anair-pump mechanically connected thereto, a compressed-air reservoirconnected to said pump, and also connected to said engine at a pointwhere the working pressure is below the highest working pressure of thesteamengine, and valves in the connections from said reservoir to thepump and the engine, substantially as and for the purpose set forth.

5. In a power plant, the combination of a compound steam-engine, anair-pump mechanically connected thereto, a reservoir connected to saidpump, and also connected to said steam-engine at a point between thehigh and low pressure cylinders, and valves in the connections of saidreservoir to the pump and steam-engine.

6. In an apparatus for generating and storing power, the combination ofa plurality of prime movers operating by fluid-pressure, afluid-pressure pump connected with each prime mover and operatedthereby, a reservoir connected with said pumps, an auxiliaryfluid-pressure device capable of acting either as a motor or as a pump,and means for causing said auxiliary device to absorb a portion of theenergy generated by the prime movers and store fluid-pressure in saidreservoir when desired, and means for applying the,

stored pressure to cause said auxiliary device to generate energy toasslst the prime movers as desired.

WILLIAM J. CLARK.

